Originally posted by Fl_Gulfer What is that thing on the Mount end?
An adapter of some form with a flange for screwing the lens to a camera with 4 screws.
The lens has been converted to something other than K mount; I would guess it was used on a video or movie camera based on the length of the adapter. Note that the A lock on the aperture ring is missing. Who knows how much of the K mount, its electrical and AF contacts still exist under the adapter and how much it would cost to convert back to K mount as anything other than a manual focus, manual aperture lens.
I wouldn't touch it for 10% of that price without inspecting the lens in person and disassembling the conversion to see what damage (if any) was done by whoever modified it.